360 DR. SARAH М. BAKER AND MISS M. H. BOHLING ON 
ecad coralloides shows only slight curling. From this we think it probable, 
first, that the phenomenon of twisting is correlated with access of nutrient 
salts, and, secondly, that it is connected with the recumbent habit of the 
plants. Salt-marsh Fucoids are only lifted gently by the tide when it covers 
the marsh and deposited again at the ebb in their original position ; this 
A. 
Fi. 13.— Fucus vesiculosus proliferations experimentally produced on the Samphire Marsh, 
Blakeney. Nat. size. 
may be well seen in the free-growing Pelvetia of the Blakeney marshes. 
Hence in the intertidal periods one side of the plant, the lower, is always in 
contaet with wet soil charged with nutrient salts, and tends to lengthen, and 
so contortion of the thallus results. In the free-growing Pelvetia this takes 
the form of curling, which is always away from the soil. This tendency to 
spirality or contortion disappears in a plant like Кисиз spiralis var. пана, 
which does not grow in the placid seclusion of the marsh, but upon the mud- 
